<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
  <link href="css/bootstrap.min.css" rel="stylesheet"/>
  <script src="js/jquery-3.3.1.min.js"></script>
  <script src="js/bootstrap.min.js"></script>
    <title>图标</title>
</head>
<body>
<button class="btn btn-primary">
  <span class="glyphicon glyphicon-search"></span>
  搜索
</button>
<button class="btn btn-warning">

  <span class="glyphicon glyphicon-asterisk"></span>
  警告
</button>
</body>
</html>